The present invention relates to a pushcart, and more particularly to a pushcart having a leg position control gear. The leg position control gear includes a locking part and a push part. When two rear legs of the pushcart are in an extended position for use, the legs are locked by the locking part from moving; and when the push part is moved upward, the legs are released from the locking part and could be moved to a collapsed position for convenient storage.
A pushcart having collapsible legs is particularly suitable for use as a medical aid.
FIGS. 1 and 2 show a conventional pushcart with collapsible legs disclosed in Taiwanese Patent Application No. 88209563 entitled xe2x80x9cAssisting Pushcartxe2x80x9d. The pushcart 10 includes a front frame 20 and a rear support 30. The rear support 30 may be moved between an extended position and a collapsed position relative to the front frame 20 through a stop member 40 and a safety lock 50. By inward pushing a control end 512 of a locking part 51 of the safety lock 50, an elastic element 521 is compressed and a lower end surface 511 of the locking part 51 is temporarily moved away from an open space 41 defined by the stop member 40. At this point, a cross bar 33 of the rear support 30 is allowed to move up and down in the open space 41. When the cross bar 33 is moved to a desired position in the open space 41, the control end 512 is released and the elastic element 521 brings the lower end surface 511 of the locking part 51 to press against the cross bar 33, preventing the same from moving in the open space 41 and holding the rear support 30 to the extended position. The assisting pushcart 10 with the rear support 30 in the extended position helps an invalid, an aged or a patient to move safely.
There are drawbacks existing in the above-described conventional pushcart. Generally, the elastic element 521 must have a considerably strong elasticity for it to have sufficient restoring force when a compressive source is removed, so that the lower end surface 511 of the safety lock 50 could effectively press against and lock the cross bar 33 in place. That is, the elastic element 521 must have a high coefficient of elasticity. In the event the elastic element 521 has not sufficient elasticity and fails to effectively press against and hold the cross bar 33 in place, the safety lock 50 would disengage from the stop member 40 and result in danger and injury to a user. However, when the elastic element 521 has a strong elasticity, the user would have to exert a big force to push and hold the control end 512 of the safety lock 50 to keep the lower end surface 511 disengaged from the cross bar 33 in order to move the rear support 30 into the collapsed position. This design causes inconvenience to users and is not suitable for the invalid, the aged or the patient who usually has difficulty in exerting a big force to hold the control end 512 to a depressed position.
Moreover, the safety lock 50 is caused to disengage from the cross bar 33 by pushing the control end 512 toward the stop member 40. The control end 512 is very easily subjected to a force in a direction toward the stop member 40 due to unexpected collision and undesirably unlocks the cross bar 33, resulting in unwanted collapse of the rear support 30 and accordingly dangers to the user.
Another problem with the above-described conventional pushcart is there are gaps existing between two wing portions 43, 44 of the stop member 40 and an outer wall of the locking part 51. When the locking part 51 is moved toward or away from the stop member 40 during the operation of extending or collapsing the rear support 30, such gaps tend to pinch the user""s finger or even the user""s loose clothes and cause dangers to the user.
A primary object of the present invention is to provide a pushcart with a leg position control gear that enables a user to apply only a minor upward force at a push part of the leg position control gear to easily move a rear support of the pushcart into a collapsed position for convenient storage, and to directly pull the rear support away from a front frame of the pushcart to move into an extended position without exerting any force at the push part.
Another object of the present invention is to provide a pushcart with a leg position control gear that includes a U-shaped push part to enclose a locking part of the leg position control gear, so that a user would not be pinched by any gap between the locking part and the push part while extending or collapsing the legs of the pushcart.
A further object of the present invention is to provide a pushcart with a leg position control gear that requires an upward force to move a push part of the leg position control gear to unlock two legs of the pushcart, so that the legs are not easily unlocked to collapse by a forward force applied on the push part due to unexpected collision or touch of the push part.
A still further object of the present invention is to provide a pushcart with a leg position control gear that includes a push part to elastically push a lever to lock legs of the pushcart in place or to release the legs. The whole leg position control gear has simple structure and can be easily assembled to enable reduced manufacturing cost of the pushcart.
To achieve the above and other objects, the pushcart of the present invention is characterized in a leg position control gear that includes a locking part fixedly mounted to a predetermined position at a rear side of a front brace of the pushcart, so that an open space is defined between the locking part and the front brace for a cross bar of a rear support of the pushcart to up and down movably locate therein; a lever pivotally mounted in a through hole on the locking part, so that a lower arm thereof could be turned forward into the open space to press against the cross bar located in the open space; and a push part up and down movably connected to a rear side of the locking part, so that an elastic element mounted to an inner side of the push part normally contacts with and pushes the lower arm of the lever forward.
When the rear support is in a collapsed position closed to the front brace of the pushcart, the cross bar is located at an upper portion of the open space. When the cross bar is moved downward in the open space, the lower arm of the lever is pushed rearward by the cross bar to compress the elastic element, allowing the cross bar to move to a lower portion of the open space and the rear support to move rearward to an extended position. At this point, the lower arm of the lever is pushed forward again by the elastic element to firmly press a lower end against the cross bar and thereby lock the rear support in the extended position without moving.
When rear support is in the extended position and the push part of the leg position control gear is lightly pushed upward, the push part turns the lever to disengage the lower arm of the lever from the cross bar, allowing the cross bar to move upward in the open space and pull the whole rear support toward the front brace into the collapsed position.
The leg position control gear for the pushcart of the present invention ensures safe locking of the rear support of the pushcart to the extended position for use. A user needs only to push of the cross bar downward to move the rear support rearward to the extended position, or to upward push the push part to allow the rear support to move into the collapsed position. The pushcart of the present invention is therefore simple and safe for use.